Rock taken for assay from the roof, or "back", of a mine opening.
Waste rock or soil used to fill a void created by mining. Mine waste or rock used to support the roof of a mine chamber after coal removal. Also, the act of placing such material.
The natural level of some physical property in the environment. Particularly, small-scale radioactivity present in almost all rocks on Earth.
Market condition where the futures price of a metal is lower in distant delivery months than in nearer delivery months. Opposite of contango.
A formal summary of a company's assets, liabilities, and net worth at a particular point in time. Also called a statement of condition.
Ore grinding device consisting of a rotating cylinder filled with steel balls. Crushed ore is placed in the cylinder and eventually ground as fine as sand-size.
Sedimentary deposits consisting of thin layers of iron minerals alternated with beds of silica. The most important worldwide sources of mined iron. Most banded iron formations (or BIFs) formed during the Proterozoic era, from 2.5 to 1.8 billion years ago, the layering being controlled by fluctuations in atmospheric oxygen. Various classes are recognized, distinguished mainly by the mineralogical form of iron - sulfide, oxide, carbonate, or silicate.
Said of rock or vein material containing no minerals of value, and of strata without coal, or containing coal in seams too thin to be workable.
Enclosing part of a mine to prevent inflow of noxious gasses from a mine fire or an explosion.
Solid blocks of coal left between two mines or sections of a mine to prevent accidents due to inrushes of water, gas, or from explosions or a mine fire.
A clay-rich deposit formed of material dragged along at the base of a glacier.
Dark-colored, silica-poor volcanic rock composed primarily of plagioclase and pyroxene, sometimes with olivine and quartz. Produced at ocean island volcanoes such as Hawaii's Kilauea, and various locations on the continents. Massive outpourings of basalt, known as flood basalts, have occurred periodically throughout geologic time, producing features such as the Deccan Traps in India and the Columbia Plateau in the northwestern U.S. Basalt horizons occasionally host economic deposits of gold, copper, chromite, and other metals.
Center from which exploration activity is conducted, usually in a remote location.
Non-precious metals such as copper, lead, zinc, aluminum, and nickel valued mainly for use in industrial applications. Base metals tend to be more chemically reactive than precious metals.
The underlying or older stratigraphy within a given area. Often refers to igneous or metamorphic rocks of Precambrian age which may be covered by younger sedimentary or volcanic rocks. Sometimes called the crystalline basement. The contact between basement and overlying rocks can be an important exploration target, particularly for uranium.
Somewhat outdated term for igneous rocks relatively low in silica, composed mostly of dark-colored minerals, such as basalt. Similar to "mafic" and opposite of "acidic".
A dome-like mass of igneous rock, often granitic, with a lateral extent generally more than 40 square miles, and no observable bottom. Batholiths are formed almost exclusively along margins between colliding tectonic plates, by numerous pulses of rising magma. Tin and tungsten deposits can be associated with such granitic bodies.
Rock composed of hydrous aluminum oxides and aluminum hydroxides. A residual deposit, formed by the transport and concentration of soil aluminum by rainwater in tropical and subtropical areas. Bauxite is the world's principal source of commercial aluminum, with large resources found in Australia, Brazil, Guinea, and Jamaica. A type of laterite deposit.
A bar or straight girder used to support a span of roof between two support props or walls.
The creation of a strong, inflexible beam by bolting or otherwise fastening together several weaker layers. In coal mining this is the intended basis for roof bolting.
A prolonged period of declining prices for shares, goods, or other financial instruments.
A surveying term used to designate direction. The bearing of a line is the acute horizontal angle between the meridian and the line. The meridian is an established line of reference. Azimuths are angles measured clockwise from any meridian.
A plate used to distribute a given load. In roof bolting, the plate used between the bolt head and the roof.
A stratum of coal or other sedimentary deposit.
The arrangement of sedimentary rock layers, or beds. The physical and structural characteristics of a package of rock beds and the contacts between them. Also, stratification or layering.
A looped belt on which coal or other materials can be carried and which is generally constructed of flame-resistant material or of reinforced rubber or rubber-like substance.
A roller, usually of cylindrical shape, which is supported on a frame and which, in turn, supports or guides a conveyor belt. Idlers are not powered but turn by contact with the moving belt.
A belt pulley, generally under a conveyor belt and inby the drive pulley, kept under strong tension parallel to the belt line. Its purpose is to automatically compensate for any slack in the belting created by start-up, etc.
One of two or more divisions of a coal seam separated by slate or formed by the process of cutting the coal.
Small scale assaying set up.
The treatment of mined material, making it more concentrated or enriched.
A clay formed by chemical alteration of volcanic ash deposits, with great capacity for absorbing water. Bentonite is used as a thickening agent in oilwell drilling muds because of its ability to swell eight times in size when hydrated.
A pile or mound of material capable of restraining a vehicle.
An iron ore with phosphorus content lower than 0.045%.
A streak of impurity in a coal seam.
An ore-treatment process using bacteria to aid the dissolution and subsequent recovery of metals. Bioleaching can be accomplished both in-situ and within a treatment plant ("stirred tank leaching").
A potassium-magnesium-iron mica. Common in igneous, metamorphic, and sedimentary rocks.
The cutting end of a drill frequently made of an extremely hard material such as industrial diamonds or tungsten carbide.
A middle rank coal (between subbituminous and anthracite) formed by additional pressure and heat on lignite. Usually has a high Btu value and may be referred to as "soft coal."
A term generally applied to carbon dioxide. Strictly speaking, it is a mixture of carbon dioxide and nitrogen. It is also applied to an atmosphere depleted of oxygen, rather than having an excess of carbon dioxide.
Seafloor vent expelling hydrothermal fluids at temperatures over 350 degrees centigrade, found in areas of active ocean floor spreading and subduction. The name refers to black precipitates formed when the hot, sulfide-laden fluids come in contact with cold seawater. Ancient black smokers may have played a role in forming VMS-type massive sulfide ore deposits.
A term used by miners to describe sphalerite (zinc sulfide), especially darker varieties, which used to be considered a nuisance component of lead ores. Also used in Arkansas to describe dark, carbonaceous clay or earth associated with coal seams.
A cylindrical reaction vessel lined with heat-resistant bricks, into which "blasts" of high-pressure hot air and other gases are blown in order to produce metal from ore. Most commonly used in creating iron for steel-making, but also used to process lead, copper, tin, and other metals.
A mine employee who loads, primes, and detonates blasting materials.
A drillhole filled with explosives in order to blast rock loose.
Any material consisting of a mixture of a fuel and an oxidizer.
A detonator containing a charge of detonating compound, which is ignited by electric current or the spark of a fuse. Used for detonating explosives.
Electric circuits used to fire electric detonators or to ignite an igniter cord by means of an electric starter.
Bleeder or bleeder entries
Special air courses developed and maintained as part of the mine ventilation system and designed to continuously move air-methane mixtures emitted by the gob or at the active face away from the active workings and into mine-return air courses. Alt: Exhaust ventilation lateral.
Bulk Leach Extractable Gold, more commonly shortened to BLEG, is a geochemical sampling and analysis tool. It was developed in the early 1980s to address concerns relating to the accurate measuring of fine grained gold, and involves cyanide leaching relatively large (two to five kilos) samples for gold.>> (Bulk Leach Extractable Gold) samples on the west side. The first target they identified was Acrobat, currently in our West Pequop property JVed with Agnico Eagle. They did some early drilling there, which we followed up on with IPO money in the fall of 2005.
Intermediate product in the copper refining process, containing about 99% copper. Produced by oxidizing copper matte (mixture of copper and iron sulfides) to remove iron and reduce copper to its elemental form. So-named because the process forms bubbles of sulfur dioxide on the surface of the copper. Blister copper must be further refined before use in industrial applications.
A low-cost method of bulk mining in which large blocks of ore are undercut and the supporting pillars are blasted away, causing the ore to cave under its own weight.
A standard-sized block of shares, usually purchased by investors at a discount. In most cases a board lot is 100 shares, although some exchanges, such as Toronto, offer 500- and 1,000-share board lots.
The turning force in foot-pounds applied to a roof bolt to achieve an installed tension.
Note issued by a corporation or government as an agreement to pay the holder a certain amount of interest over a given period of time.
A powered steel arm used to support drifters, manbaskets, and hydraulic hammers.
Any deep or long drill-hole, usually associated with a diamond drill.
Any member of the managerial ranks who is directly in charge of miners (e.g., "shift-boss," "face-boss," "fire-boss," etc.).
Floor or underlying surface of an underground excavation.
A short raise or opening driven upward from a drift in order to mine overlying ore or permit access.
A small, portable magazine used to store limited quantities of explosives or detonators for short periods of time at locations in the mine which are convenient to the blasting sites at which they will be used.
Brattice or brattice cloth
Fire-resistant fabric or plastic partition used in a mine passage to confine the air and force it into the working place. Also termed "line brattice," "line canvas," or "line curtain."
An abrupt geologic discontinuity such as a fault, fracture, or unconformity.
The line that roughly follows the rear edges of coal pillars that are being mined. The line along which the roof of a coal mine is expected to break.
A passage for ventilation that is cut through the pillars between rooms.
A surface, or face, being worked within a mine. "Before breast" refers to material still ahead to be mined.
Coarse-grained sedimentary deposit made of angular fragments of rock surrounded by finer material. Breccias form when rock is broken and then redeposited by hydrothermal activity, faulting, or volcanism. Such rocks sometimes indicate a nearby mineralized system.
The process of forming a breccia.
A short conveyor hung from the boom of mining or lading machine or haulage system with the other end attached to a receiving bin that dollies along a frame supported by the room or entry conveyor, tailpiece. Thus, as the machine boom moves, the bridge conveyor keeps it in constant connection with the tailpiece. Also known as a bridge carrier.
Mine ore broken by blasting but not yet brought to surface.
A low place in the roof of a mine, giving insufficient headroom.
A pocket compass used for sighting lines as well as measuring strike and dip of geologic horizons.
Digging up the bottom or taking down the top to give more headroom in roadways.
British thermal unit. A measure of the energy required to raise the temperature of one pound of water one degree Fahrenheit.
The fine particles of coal or other material resulting form the boring or cutting of the coal face by drill or machine.
Large-scale extraction of many thousands of tonnes of ore per day.
A large rock sample, often hundreds of tons, selected to be representative of a potential orebody. Used to determine metallurgical characteristics.
A prolonged period of increasing prices for shares, goods, or other financial instruments.
Prospector's term for white, coarse-grained quartz bearing little or no mineralization.
Bars or ingots formed of metal. Usually refers to precious metals, such as gold bullion.
A violent dislocation of the mine workings which is attributed to severe stresses in the rock surrounding the workings.
A short, poorly defined vertical cleavage plane in a coal seam, usually at right angles to the long face cleat.
A coal mining term that has different meanings in different locations. It can be synonymous with panel entry, submain entry, or in its older sense it refers to an entry that is "butt" onto the coal cleavage (that is, at right angles to the face).
An accessory metal or mineral product recovered during processing of ore. Silver is often a byproduct of lead, zinc, copper, and gold treatment. Gold can yield nuisance byproducts such as arsenic and mercury.